It is known that catalyst components for the polymerization of olefins comprising a titanium compound supported on a magnesium halide in active form can be obtained in spherical particle form suitable for the development of polymers with optimum morphological characteristics. Components of this type are described in U.S. Pat. Nos. 3,953,414 and 4,399,054. Specifically, the polymers obtained with the catalysts of U.S. Pat. No. 4,399,054 are in spherical particle form having high flowability and high bulk density.
The porosity (around 10% expressed in percentage of voids) and the surface area, however, are not sufficiently high to allow their use, particularly in the field of masterbatch preparation when said masterbatch contain a significant quantity of pigments and/or additives.